5 replies to this topic

[DrMcNasty]

Model: Mini 1000
Year: 1979
Description of problem (please be as in depth as possible):

I am having a brutal issue trying to get ready to run the rest of the brake lines on my project car.
As you can see attached, I have a master cylinder (I know it isn't the correct one for the year) and the brass block that mounts on the fire wall. I am trying to find fittings that match these and am not having any luck at all. The standard 1/4 and 3/8 are not fitting properly. The 1/4 seems slightly loose, and the 3/8 is threading in about 1 turn then it seems like the threads are locking. I can take the bleeder screw though and thread it all the way in by hand without a problem.

Question 1: What are the 2 fitting sizes on the attached items in the picture. The master cylinder has 2 fittings that are the same size by visual reference, and the brass block has 2 different size fittings. 3 are one size and 2 are the other.

Question 2: Does it matter which connections run from the master cylinder to the brass block. I understand that the front and rear systems are separated from side to side and I am making the assumption that the side with the 3 fittings (all the same size) is the side that runs to the front system in the car.

Example:

Connection A from Master Cylinder goes to Connection E on the brass block.
Connection B from Master Cylinder goes to Connection B on the brass block.
Connection C on brass block goes to the front brake system on the front sub frame.
Connection D on the brass block runs the length of the car to the back, where it will meet a 3 way brass splitter and then run to each of the brake sides.
Connection A on the brass block would be the bleeder for the brass block. And is this the right location for the bleeder for the brass block assuming the mounting loop hole is the "top".

Question 3: What size are the fittings on the sub frame side of the read flex hoses, as I will need to match those as well since they will need to feed to a brass 3 way splitter block on the rear sub frame that has yet to be acquired.

Any non-standard parts that might be involved with the problem?

I am in Canada, so I do not know if these fitting sizes may be different since they may be UK parts, I honestly do not know since the car was not complete when I started the restoration.




Please help a frustrated guy trying to get his first mini built.

Nasty

[Ethel]

I'd expect them to all be 3/8 - 24 UNF if they are original Mini parts as they look to be.

[DrMcNasty]

They are 3/8", but the threading isn't normal on the brass block. I tried a standard 3/8 fitting here and it doesn't thread in. Also the brass block has 2 different size fittings, I believe they are 3/8" and 1/4" but I can't seem to confirm that.

[mini7boy]

there is a master cylinder, named GMC227 I believe, which has metric fittings, 10mm and 12mm.

I don't know if this is your problem or not.

A conversion "kit" is available: http://www.minispare..... L/H/DCONVE...

[Cooperman]

This area is, potentially, the most unsafe bit of automobile engineering ever seen.
In Rover's wisdom, they used METRIC threads for the connections into the limiting valve and IMPERIAL threads for all the other brake unions. No wonder their comnpany failed eventually.
However, if you buy a set of brake pipes it is easy to try to fit the imperial fittings into the metric holes and, unfortunately, they actually appear to fit, until you try to bleed out the system, that is.
Mini Spares (and others) sell the pipes with the correct ends but you must ensure that you fit them the right way around.

[Ethel]

that's not a gmc227, it looks like the very first type of dual master used on Minis. I would have thought the brass shuttle valve would have predated the metric fittings. There are some visual clues, only UNF holes will be counterbored, but not all UNF holes.